We report, for the first time, the design and simulation of electrostatic MEMS comb-drive actuators incorporating gray-scale technology to tailor actuator properties. Specifically, 3-dimensional comb-fingers and suspensions enable customized displacement characteristics and lower driving voltages without increasing the device footprint. The local height of each comb-finger is varied using gray-scale technology to modify the change in capacitance with position, thereby altering the generated force. The displacement characteristics of various comb-finger geometries were simulated using analytical approximations and finite element analysis (FEMLAB). Simulations show that variable height comb-finger designs may reduce the local change in capacitance (or force) by up to 75%, resulting in increased displacement resolution. We also show that gray-scale technology is capable of simultaneously reducing the height of comb-drive suspensions, causing a corresponding reduction in spring constant for lower driving voltages. The design and simulation of variable height comb-drives is presented along with experimental confirmation of the simulated performance.